The corrosion behavior of two Al- Li-Cu-Zr-Ge alloys, with and without Mg, was studied. The types of corrosion tests conducted included exfoliation corrosion, crevice corrosion, constant immersion studies and anodic polarizations. The alloys were tested in both the underaged and overaged tempers. The heat treatments resulted in significant microstructural differences due to the precipitation of numerous metastable and equilibrium phases.

The addition of magnesium results in a more consistent corrosion behavior with aging time, as well as a lower susceptibility to general corrosion, a higher rate of electrochemically induced corrosion and the development of a type of pit not seen in the alloy without magnesium. Overaging increases the resistance to exfoliation corrosion and to electrochemically induced corrosion. Both alloys exhibit good resistance to crevice corrosion. Finally, evidence will be presented to suggest that lithium is not the only reactive species present in these alloys, and that in fact, the corrosion behavior of these alloys appears to be more dependent on the various precipitate phases present due to other alloying additions.

Subject
Pits, Precipitation (solids), Metal surfaces, Transmission electron microscopy, Magnesium alloys, Corrosion behavior, Crevice corrosion, Lithium, Immersion, Aluminum alloys, Grain boundary, Alloys, Aging
© 1986 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1986
Association for Materials Protection and Performance (AMPP)
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